Partial support is requested for the 2005 Gordon Research Conference on Motile and Contractile Systems to be held July 10- July 15, 2005 at Colby-Sawyer College in New Hampshire. The purpose of this conference is to encourage the transfer of ideas and information within the community of scientists who work at the forefront of cytoskeletal research, an area that has long been recognized as critical for understanding fundamental biological processes. Cytoskeletal elements are essential for life in eukaryotes, making central contributions to cell motility, cell signaling, membrane trafficking, cell division, cell polarity, and the development of multicellular organisms. Actin, microtubules and motors are important for many normal physiological functions including wound healing, pathogen-cell interactions, celli-mediated immunity and embryogenesis. Moreover, cytoskeletal defects underlay many pathological human conditions including musculoskeletal and neurodegenerative diseases, ontogenesis, respiratory diseases, infertility, and congenital blindness and deafness. The 2005 conference will focus on dynamics of cytoskeletal elements in living cells, and the functions of these complexes in cell locomotion, intracellular transport of membrane-bounded vesicles and mRNAs, wound healing, chromosome segregation and cell division, and tissue morphogenesis in development. A special session will be devoted to pathological conditions caused by mutations in genes encoding cytoskeletal proteins. Because of its breadth and interdisciplinary nature, the Motile and Contractile Systems Gordon Conference has continued to play a seminal role in the field, despite the proliferation of subspecialty meetings. The conference will feature a Keynote Lecture by Dr. Joel Rosenbaum who will discuss the biological role of intraflagellar transport and pathological conditions caused by its deficiency. Approximately 60 outstanding research scientists will make formal presentations in eight lecture/discussion sessions. About one-third of these presentations will be selected from the submitted abstracts to encourage participation by outstanding new investigators, postdocs and students. Conferees who do not make oral contributions will be encouraged to present their recent work in a poster format.